This invention relates to stoppers for medical containers and, more particularly, to stoppers for blood collection tubes and the like which enable the use of such collection tubes with oversized tube holders.
The most common sealed fluid sample containers are sealed and evacuated blood sample collection tubes used for receiving and preserving for testing samples of fluid blood. When drawing or collecting blood samples sealed and partially evacuated glass collection tubes are frequently used with a tube holder sized to receive collection tubes having their stoppers in place. The tube holder also generally includes a needle cannula extending axially therefrom. In order to permit blood to pass into the collection tube, the stopper is inserted into the tube holder and one end of the double-ended needle or the like punctures and holds the stopper and collection tube in place until the desired volume of blood sample or other substance has been collected. Brush U.S. Pat. No. 4,150,666 discloses a blood collection tube holder having a substantially tubular body open at one end to receive and guide a collection tube as it moves thereinto. The opposite end of the tubular body is closed by a wall in which a double-ended needle cannula is positioned. One end of the needle projects outwardly from the end wall of the holder for insertion into a patient's blood vessel while the opposite end of the needle extends axially in the tube holder and is positioned to penetrate the stopper on the sample tube and establish fluid communication with the interior of the collection or sample tube. With the known constructions, however, it is often necessary to draw a number of blood samples for different tests from the same patient while maintaining the same tube holder needle in the vein of the patient to avoid subjecting the patient to multiple punctures. Recently the use of relatively small blood collection tubes, such as 10 millimeter tubes which accommodate samples of two to four milliliters in volume, has been preferred and has become common practice due to the small sample sizes required for many of the blood tests most frequently performed. Other more extensive blood tests, however, may require larger samples and hence larger volume collection tubes and difficulties can occur if the same tube holder is used with tubes of widely differing sizes. Furthermore, the technician may find it difficult to maintain a holder, sized for a relatively large collection tube, steady and the double-ended needle in the patient's vein while trying to penetrate the center portion of a smaller tube stopper with the opposite end of the same needle. Also, failure to properly align the needle with the center portion of the small tube stopper can result in occluding or blocking the end of the double-ended needle in the stopper side wall. Still further, use of relatively small collection tubes with small stoppers approximating the diameter of the tube makes it difficult for laboratory personnel to remove the stopper without getting blood or serum on their fingers. This can make the handling hazardous especially when samples may contain infectious agents, such as hepatitis or AIDS virus. Therefore, it is desired to avoid such difficulties while at the same time being able to employ a single tube holder for collecting several blood samples in collection tubes of differing sizes.
The present construction overcomes these and other problems associated with the known prior art and includes a tube holder designed to guide the collection tube and its stopper so that the end portion of the needle in the holder device will penetrate a central thinner diaphragm portion of the stopper and move through the stopper diaphragm to communicate with the interior of the sample tube, thus avoiding the possibility of moving the open end of the needle against the side wall of the stopper or of the sample tube and blocking or occluding the needle. The present stopper construction is relatively inexpensive to make, is easy to use, can be used with containers of differing size and is relatively fail safe.